package com.longge;

public class PruneTree {

    public TreeNode pruneTree(TreeNode root) {
        if (root==null) return null;
        root.left=pruneTree(root.left);
        root.right=pruneTree(root.right);
        if (root.left==null&&root.right==null&&root.val == 0) return null;
        return root;
    }
}
